Leases - Lease Cost and Other Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Finance Leases [Abstract]
Amortization of ROU assets	$ 2.6	$ 2.7
Interest on lease liabilities	0.4	0.5
Operating leases	7.7	8.1
Short-term lease cost	1.1	0.9
Variable lease cost	1.9	1.6
Total lease cost	13.7	13.8
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows - finance leases	1.8	1.4
Operating cash flows - operating leases	8.0	8.8
Financing cash flows - finance leases	2.6	3.0
Right-Of-Use Asset Obtained In Exchange For Lease Liability [Abstract]
ROU assets obtained in exchange for new finance lease liabilities	1.1	3.4
ROU assets obtained in exchange for new operating lease liabilities	$ 2.4	$ 3.3
Finance leases
Remaining lease term (in years)	6 years 1 month 6 days	6 years 2 months 12 days
Discount rate	4.80%	5.00%
Operating leases
Remaining lease term (in years)	4 years 6 months	4 years 9 months 18 days
Discount rate	5.00%	5.10%